Receiver for electromagnetic waves.



R. A; FESSENDEN.

RBGBIVBR FOB ELEGTROMAGNETIG WAVES.

APPLIOATION FILED MAY 4, 1904. v 1,022,539. Patented Apr. 9,1912.

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R. A. FESSENDEN. RECEIVER FOR ELEGTROMAGNETIG WAVES.v

APPLmATIoN FILED MAY 4^, 1904.

1,022,539. Patented Apr. 9, 1912.

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FISE- bq Muy UNITED sTATEs PATENT oEEicE.

BEGINALID A. FESSENDEN, 0F WASHINGTON, D'JIS'IRJIC'I OF COLUMBIA, ASSIGNOB. T0 THE NATIONAL ELECTRIC SIGNALING COMPANY, 'OF PITTSBURGH, PENNSYLVANIA,

A CORPORATION 0F NEW JERSEY.

RECEIVERV FOB ELECTROMAGNETIC WAVES.

speiacauon of Letters Patent.

Patented Apr. 9, '1912.

To all whom t may concern Be it known thatI, REGiNALD A. FiissEN- DEN, a citizen of the United States., residing at Washington, in the District of Columbia, have invented certain new and. useful Improvements in Receivers for Electromagnetic Waves, o f which the following is a specification.

My invention relates to receiving devices of the type in which the currents to be detected, and also the current from a local circuit, both flow through a minute cross-section of fluid, and the energy of the currents to be detected causes a variation in the amount of current in the local circuit.

The theory of the action of this radically new type of receiver, so far as it has been analyzed by the applicant, is given in U..S. Patent Reissue No. 12,115.

The invention will be more fully understood from the following description and claims taken in connection with the accoms panying drawing, in which- 1 Figure 1 is a vertical section of one form of a cell embodying my invention; Fig. 2 a vertical section of another form of electrode; Fig. 3 a vertical section showing an'embodiment of my Vinvention including parts particularly adapted for use with the form shown in Fig. 2; Fig. 4 is a toj` plan view of the arrangement shown in ig. 3, and Fig. 5 illustrates a modication of my improvement.

The receivers shown in said drawings embody a characteristic feature of the re-v Ceivers of said prior patent Reissue No. 12,115, in that in lthem the current is caused to low through a very small cross-section of fluid. In most of the forms described in said patent, this small cross-section is regu-k lated by regulating the depth of immersion of a ne Wire in a liquid, but in some forms as for example that of Fig. 8 of said patent, the immersion is determined definitely by causing the electrode to project a determined amount from a fine glass tube in which it is sealed.

In the device forming the subject-matter of this application, the elect-rode' 1 which is in the glass tube may preferably be ground off so as to be practically level or flush with the surface of the material in which it is sealed or held, the current iiowing through A Application led Kay 4, 1904. Serial No. 208,803.

the minute cross-section of'liquid contacting with the ground-oit crosssection of the end of the` conducting electrode. This electrode should not be in close proximity tothe other electrode, as thereby capacity effects would be produced which would result in a storing up of energy which would then A'become unavailable for producing an indication. In

order to avoid any possibility of rectif-ying I the currents which are to be detected, the voltage on the local circuit should be so high that a current flows continuously, and not merely when the currents to be detected are passing, as is the condition in rectifiers by reason of the impressed volta e being lower than the decomposition of t e electrolyte.v

Furthermore the electrode 1 and the other electrode 4 should be so arranged that the lines of current flow spread out in a radial direction from the elect-rode 1, and thereby localize the effective resistance in the immediate neighborhood of the terminal of the electrode. Also it is advisable to arrange the electrodes at a distance apart at least many times the diameter of the wire at 1.

In Fig. 1 the electrode 1 is sealed in the glass 2 and ground oif flush, and is placed near the bottom of a small glass vessel 3, and projecting upward, the other electrode 4 also being immersed in the liquid. I prefer to yarrange the ground-o` surface of the terminal of electrode 1 in a horizontal position within the body of the liquid, directed toward the surface thereof, and also arranged at the apex of a projection as shown. One object of this is to permit the free detachment of any gas that may form on the terminal, by reason of the buoyant eilfect of the gas.

Very much the same function can be served by utilizing the arrangement of Fig. 2, sealing the whole electrode sheath into the body of the vessel 3 in place of the conical projection 2 shown in said Fig. 1. The device of Fig. 2 reerred to is a small glass tube of an internal diameter of' about .005k of an inch with a platinum wire .0005 of an inch sealed into the ends and one end ground Hush with the glass so that the wire is exposed only on its end surface. In Fig. 1 the lar er electrode is formed by a wire 4, preferaly platinum, sealed in the Walls of the vessel 3 so as to be below the electrode 1.

down. along its sides. The construction. shown in Fig. 1 gives highly uniformly' good results.

The gla'ss tube with the ush terminal thus formed is shown in Figs. 3 and 4 as mounted by Vclamping in a support-ing bracket 5 by spring clip 6. This bracket is pivotally secured at 7 on the end of an arm 8, rotatably and longitudinally adjustable in a head 9 in which it is secured by screw 10. The mounting 9 is also adjustably' fixed on a vertical post 11.

The ground oil' tip or terminal of the electrode terminal 1- is arranged adjacent to a disk 12 of conducting material, preferably brass. having clamped thereon by the clamping ring 13 a moisture-retaining covering 14, preferably composed of an inner layer of absorbent material and an outer layer of soft material such as cotton velvet. This disk 12 is mounted upon a shaft 12l driven by clock Work 15 through an intermediate rubber coupling 16 to prevent transmission of vibration or shock from the clock Work to the disk.

The terminal of electrode 1, as in Fig. 1 or Fig. 3, is immersed in an electrolytic or conducting solution which may be preferably'dilute caustic potashor dilute nitrate or carbonate of soda; these may be mixed with glycerin to prevent evaporation and crystallization.

The usual receiving circuit leads are connected tothe binding posts 17 and 18. The post 18 is clamped in any desired angular adjustment by means of the thumb nut 19, and this adjustment is used to vary the tension of a spring contact 2O leading to a sleeve 21 on shaft 12a.

Rotation of the disk 12 tends to brush or wipe away the minute gaseous formations tending to form on the terminal of electrode 1. As shown the disk supports a surface of soft material moistened with the electrolyte, but it is obvious that the device may be arranged the same as shown in Fig. 3 with a receptacle containing a considerable amount of liquid substituted for said moistened surface 14.-. Thus arranged, the travel of the liquid, past the terminal would tend to carry off bubbles after the same manner, though not so positively, as the cotton velvet described above. The object of both devices, as Well as the tapering ofthe sheath in Figs. 1 and 2, is to prevent the accumulation of gases on the terminals.

By the use of the present invention a larger Wire may be used Without increasing the area in contact with the fluid, because only theiend of the wire -is exposed, and the i lwhich depends the localization of the effective high resistance in the neighborhood of the exposed terminal. v

As an alternative form the glass tube containing-the sealed electrode terminal may be mounted upon an arm on a vertical rod and revolved in a bath of solution so that here again the friction of the liquid against the exposed terminal will remove any gas which may form thereon, as shown in Fig. 5. Y

Wire of platinum-iridium may be used instead of platinum as being less liable to occlude gas bubbles.

No claim is made herein to the specific construction shown in Fig. 5 as thesame forms the subject-matter of a co-pending application filed March 26th, 1907, Serial No.

364,626, (Patent No. 917,574, of Aprlfth,

- Claims:

1. A receiver for Wireless telegraphy comprising a cell having an electrode terminal immersed therein, said terminal being exposed only on its end surface, andmeans `to preventaccumulation of gas thereon, substantially as described.

2. A receiver for Wireless telegraphy comprising an electrolytic cell having an elec-v sof trode immersed therein consisting of-a Wire having a. sheath covering it except on its end surface, and means to effect continual removal of bubbles of gas tending to accumulate on the termina-l of said electrode.

3. A polarization cell adapted as a detector for wireless telegraphy having one electrode sheathed in non-conducting material except on its end surface, and another electrode of larger surface placed in the electrode.

4. The combination of a support having a detachable terminal secured theretoand consisting of a conical non-conducting sheath with a conductor extending therethrough, and means for maintaining a movin body of liquid electrolyte in contact with ne terminal of said electrode.

-liquid ofthe cell below the level of the first 5. As an article of manufacture a detachi prising an electrode .sealed in `bubbles from the electrode.

9. A receiver for wireless telegraphy comglass, and a yielding materialin contact with the electrode, and means for relatively moving they electrode and said material continually during use.

'of a porous material moistened with -a liquid 10. In a receiver for wireless telegraphy, the combination with a ine point electrode,

electrolyte and means for maintaining it in movable contactwith the electrode. 1

y11. In a receiver foiwireless telegraphy, the combination with a fine point anode, of a cathode consisting of a vessel supportin .a

liquid electrolyte and means maintalning t e electrolyte and anode in relative movement.

12. In a detector of electromagnetic waves or other feeble electrical impulses, the anodeA of a polarization cell' consisting of a fine wire surrounded by insulati material except on its end surface, such 111sulating ma. terial tapering to a nevpoint atthe end `of the wire and the wire presenting a minute surface to the electrolyte.

, 13. A sup ort, means -movement ofsaid parts. 1

20.' A receiver for wireless signalin'gicom-f prising a fine point anode, a supportl ;onf. l 'taining a liquidelectrolyte in contact' there-.iff v with and meansA for relatively'movingfs'aid j for maintaining liquid electro yte in operative relation thereto and a' detachable terminal secured to saidf support, consisting of a ne wire anda-conical Yor convergingl sheath or tube, the lpor- 'tion of the sheath about ksaid terminal being ground oi.-

14. A. support, means `for',maintaining liquid electrolyte in operative'relation thereto and a detachable terminal secured to said support, consisting of a conical or converging non-conducting-sheath or'tube and a fine terminal sealed in said conical or converging sheath, said sheathand terminal being. ground ofi' flush with each other.`

15. A receiver for wireless signaling comprising an anode of small area, a liquid electrolyte in contact therewith andmeans for relatively moving the anode and electrolyte.

16. In a receiver, a tine terminal, a suitable receptacle` for a liquid electrolyte land means forcausing relative movement of said terminal and rece tacle.

17.A non-con ucting sheath, ai minute anode and means for circulating a liquid electrolyte in contact therewith.

' 8. In a receiver, ya non-conducting sheath, a fine terminal -sealed therein and means for maintaining` andchanging a supply of liquid electrolytein contact therewith.

19. In a receiver,jf0r wireless signalin a ne point terminal, afsupport for llquid e ectrolyte and ymeans-:for producing relative support and said anode.`

Witn:

Tnoms P. BROWN, Jass'ln G. BENT..

REGINALD 

